logical {base} | R Documentation

## Logical Vectors

### Description

Create or test for objects of type `"logical"`, and the basic logical “constants”.

### Usage

    TRUE
    FALSE
    T; F

    logical(length = 0)
    as.logical(x, ...)
    is.logical(x)

### Arguments

`length` | desired length.
`x` | object to be coerced or tested.
`...` | further arguments passed to or from other methods.

### Details

`TRUE` and `FALSE` are part of the R language, where `T` and `F` are global variables set to these. All four are `logical(1)` vectors.

`is.logical` is generic: you can write methods to handle of specific classes of objects, see InternalMethods.

### Value

`logical` creates a logical vector of the specified length. Each element of the vector is equal to `FALSE`.
`as.logical` attempts to coerce its argument to be of logical type. For `factor`s, this uses the `levels` (labels) and not the `codes`. Like `as.vector` it strips attributes including names.
`is.logical` returns `TRUE` or `FALSE` depending on whether its argument is of logical type or not.

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

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